Digger tooth and mounting therefor

ABSTRACT

A digger tooth is held by a bolt against a beveled mounting so that in use the tooth is tightened against the bolt by a wedge action, so as to tension the bolt rather than to shear it. The tooth is double ended and receives the bolt in a slot to avoid shearing the bolt. The tooth is V-shaped in cross section and tapered in thickness.

O United States Patent l 13,576,082

[72] Inventor Ernest C- Lowrey 2,952,085 9/1960 Petersen 37/ 142 2315 Flower St., Los Angeles, Calif. 90007 2,992,498 7/ 1961 Mork 37/142 [21] App]. No. 816,347 3,055,128 9/1962 Edwards... 37/142 [22] Filed Apr. 15,1969 3,413,739 12/1968 Guiwot 37/142 [45] Patented Apr. 27, 1971 3,453,756 7/1969 Schroeder 37/142 3,462,861 8/1969 Kampert 37/142 3,509,648 5/1970 Smith 37/142 [54] :gggVIOUNTING THEREFOR FOREIGN PATENTS 104,951 1964 Norway 37/142 [52] US. Cl 37/142,

299/91 172,713, 172/751 Primary Exammer-Edgar S. Burr 51 lm. C1 E0219/28 and [50] Field ofSearch 37/141, 142, 142 (R), 83, 90; 172/713, 719, 732, 733, 751; 299/91-93 ABSTRACT: A di er tooth is held by a bolt a ainst a beveled [56] References Cited mounting so that ii use the tooth is tightened gainst the bolt UNITED STATES PATENTS by a wedge action, so as to tension the bolt rather than to 1,424,750 8/ 1922 Anglemeyer et a1 37/ 142 shear it. The tooth is double ended and receives the bolt in a 2,220,819 11/1940 Johnson 37/141 slot to avoid shearing the bolt. The tooth is V-shaped in cross 2,329,831 9/1943 Ferguson 37/ 141 section and tapered in thickness.

BIGGER TOOTH AND MOUNTING THEREFOR The present invention relates to digger teeth and mountings therefor.

it is an object of the present invention to provide a digger tooth and a mounting therefor such that the tooth will have a self-locking action in use.

Another object of the present invention is the provision of a digger tooth and a mounting therefor, including a bolt which is subjected principally to tensile stresses in use rather than to shear stresses.

Still another object of the present invention is the provision of a digger tooth and mounting therefor which enable positioning the tooth at various digging depths.

The invention also contemplates a digger tooth of such configuration that it will have the same or difi'erent uses even when substantially worn down.

Finally, it is an object of the present invention to provide a digger tooth and a mounting therefor which will be relatively simple and inexpensive to manufacture, easy to install, replace, maintain and repair, and rugged and durable in use.

Other objects and advantages of the present invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawing, in which:

FIG. 1 is a perspective view, generally from the underside, of a digger tooth and mounting therefor according to the present invention;

FIG. 2 is a side cross-sectional view of the invention in one position of use;

FIG. 3 is a view similar to FIG. 2 but showing the another condition of use;

FIG. 4 is a perspective view of a wedge block for use in the assembly of FIG. 3; and

FIG. 5 is a side elevational view of a trench digger embodying the present invention.

Referring now to the drawing in greater detail, there is shown a digging tooth and mounting therefor according to the present invention, for example in the environment of a trench digger 1 having a digging wheel 3 at its rear that rotates in a clockwise direction as shown in FIG. 5 as the trencher moves to the left as seen in FIG. 5 while digging a trench.

A plurality of digging buckets 5 are mounted on the periphery of digging wheel 3 and open in the clockwise direction as seen in the drawing. Each bucket 5 has a cutting edge 7 best seen in FIG. 1. As will also be seen in FIG. I, brackets 9 are welded on buckets 5 adjacent cutting edges 7, for the detachable mounting of shoes or digging teeth 11. Each bracket 9 comprises a base portion 13 secured to bucket 55 by a weld 15 and a support portion 1'7 that releasably receives the tooth 11.

Each support portion 17 is characterized by a forwardly opening slot 19 for the reception of a bolt 21, and rearwardly of slot 19, a generally forwardly and upwardly extending abutment 23 whose forward surface 25 is beveled rearwardly upwardly. The upper forward surface 26 of support portion 17, surrounding the upper end of slot 19 and forwardly of abutment 23, is flat and is disposed generally in the intended plane of the tooth 11. Surfaces 25 and 26 are disposed at an oblique angle to each other.

The tooth 11 is double ended and elongated in the cutting direction and is traversed by a slot 27 that is elongated lengthwise of tooth 11 and that receives bolt 21. Bolt 21 has a head 29 that slidably bears against the flat surface 30 about the margins of slot 27, and a nut 31 at its opposite or lower end that bears, through an appropriate washer, on the underside of parts in support portion 17 about the lower end of slot 19. About the lower end of slot 27, tooth 11 has a flat under surface 32 that bears on the flat upper surface 26 of support portion 17 of bracket 9. Tooth surfaces 3 0 and 32 are parallel to each other. The tooth 11 has a pair of digging tips 33 at opposite ends thereof, which are mirror images of each other. Each tip 33 is of V-shaped cross section with the apex of the V disposed in the forward or digging direction. The end of each tip 33 terminates in tapered edges 35 which are inclined rearwardly toward bolt 21 at an acute angle to the length of the tooth. It is especially to be noted that the cross-sectional thickness of the material of tips 33 increases progressively from the outer ends toward the central portion of tooth 11. Thus, when the tooth wears down in use, from the phantom line position of FIG. 3 to the full line position of FIG. 3, the thickness of the material of the tooth increases as the tooth shortens. The tooth thus becomes adapted, from a tooth suitable for digging at considerable depth in loose soil, to a tooth adapted to dig at lesser depth in tough or rocky material, both by virtue of the shorter length of the teeth and by virtue of their greater thickness when worn down. The teeth of the present invention are thus reversible end for end to provide two long teeth for digging in relatively soft material, and when these are worn down, two shorter teeth for digging in tougher material.

On the underside of each end of each tooth, between the portion of the tooth that has a V-shaped cross section and the central or base portion of the tooth, the tooth is provided with beveled surfaces 37 which are complementary to and individually mate with the beveled surface 25 on abutment 23 of bracket 9. Beveled surfaces 37 are thus disposed at opposite acute angles to surface 30 and at opposite oblique angles to surface 32.

As will be seen from FIG. 2 of the drawing, bolt 21 is disposed in its slot 27 with considerable play longitudinally of tooth 11. When digging thrust is exerted on tooth 11 lengthwise thereof, the beveled surfaces 25 and 37 tend to ride up on each other with a wedge action, so that the tooth tends to be forced away from bracket 9. This is opposed by bolt 21, which is accordingly tensioned. However, because bolt 21 is spaced from the end walls of its slot 27., there will be very little shear action on the bolt.

Means are also provided for effectively lengthening the tooth 11, in the form of a removable wedge 39 best seen in FIGS. 3 and 4. Wedge 39 has beveled surfaces 41 that are complementary to the beveled surfaces 25 and 37, and a flat under surface 43 that rests flat against the surface 26 of support portion 17, and dihedrally arranged surfaces 45 that are complementary to the dihedral under surfaces of the tips 33 of teeth 11. Surfaces 45 are parallel to each other and are disposed respectively at complementary acute and oblique angles to surface 26, these angles being the same as the said angles of surfaces 25 and 37. Thus, when wedge 39 is disposed between the tooth and bracket as shown in FIG. 3, it is in substantial area contact with the tooth and the bracket and the tooth is extended forwardly to a deeper digging position suitable for soft dirt and the like. The slot 27 in tooth 11 is of sufficient length to accommodate bolt 21 even in the forwardly extended position of the tooth shown in FIG. 3, without imposing substantial shear on the bolt.

In view of the foregoing disclosure, therefor, it will be evident that all of the initially recited objects of the present invention have been achieved.

Although the present invention has been described and illustrated in connection with a preferred embodiment, it is to be understood that modifications and variations may be resorted to without departing from the spirit of the invention, as those skilled in this art will readily understand. Such modifications and variations are considered to be within the purview and scope of the present invention as defined by the appended claims.

I claim:

1. A digging tooth and a support therefor, means interconnecting said tooth and support, said tooth and support having interengaging wedge surfaces such that when digging force is applied to the tooth, the tooth and said interconnecting means are forced more strongly together, said interconnecting means comprising a bolt, said tooth having a slot therethrough elongated in the direction of the length of the tooth, said bolt being disposed in said slot, said bolt having a head that bears against said tooth about the margins of said slot, and a wedge block removably positioned between said wedge surfaces to position said tooth to dig deeper when said wedge block is present than when said wedge block is absent from between said wedge surfaces, said slot being sufficiently long that said bolt is spaced from the forward end of said slot both when said wedge block is present and when said wedge block is absent.

' 2. Apparatus as claimed in claim 1, said tooth being double ended and reversible end for end and having a plane of symmetry perpendicular to and midway of its length.

3. Apparatus as claimed in claim 1, said tooth having a 

1. A digging tooth and a support therefor, means interconnecting said tooth and support, said tooth and support having interengaging wedge surfaces such that when digging force is applied to the tooth, the tooth and said interconnecting means are forced more strongly together, said interconnecting means comprising a bolt, said tooth having a slot therethrough elongated in the direction of the length of the tooth, said bolt being disposed in said slot, said bolt having a head that bears against said tooth about the margins of said slot, and a wedge block removably positioned between said wedge surfaces to position said tooth to dig deeper when said wedge block is present than when said wedge block is absent from between said wedge surfaces, said slot being sufficiently long that said bolt is spaced from the forward end of said slot both when said wedge block is present and when said wedge block is absent.
 2. Apparatus as claimed in claim 1, said tooth being double ended and reversible end for end and having a plane of symmetry perpendicular to and midway of its length.
 3. Apparatus as claimed in claim 1, said tooth having a digging tip that is V-shaped in cross section and that has the apex of the V directed forwardly in the digging direction.
 4. Apparatus as claimed in claim 3, said tip having edges that are inclined rearwardly at an acute angle to the length of the tooth.
 5. Apparatus as claimed in claim 3, said cross section increasing progressively in thickness toward said interconnecting means. 